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From: Markus Schulz <msc@antzsystem.de>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] FWMark routing trouble
Date: Wed, 02 Aug 2006 10:08:40 +0000	[thread overview]
Message-ID: <200608021208.41393.msc@antzsystem.de> (raw)

Am Samstag, 29. Juli 2006 17:33 schrieb former03 | Baltasar Cevc:
> Hi everybody,
>
> I'm trying to set up routing for 2 links to the internet on a box
> which produces traffic itself (e.g. DNS) and will route all our local
> traffic.
>
> AS one route is quick and expensive and the other one slow and cheap,
> I want to be able to route packets for some high-level protocols to
> the second link.
>
> If I correctly understood table 3-2 in
> http://www.faqs.org/docs/iptables/traversingoftables.html that is not
> possible as the routing decision is taken even before the packet
> touches netfilter for the first time.
>
>
> Is that correct? Does anybody have some hints about how to work
> around?

It's possible with Policy Routing. Look at 
http://www.policyrouting.org/PolicyRoutingBook/ONLINE/TOC.html for 
documentation about it.

(Simplest?) way to do it: (only short excerpt)

- Mark the specific application packets with iptables in PREROUTING 
chain
...
- add rules for routing fwmarked packets to seperate routing tables
ip rule add fwmark <your fwmark #1> table <routing table for slow apps>
ip rule add fwmark <your fwmark #2> table <routing table for fast apps>

- build both routing tables
ip route add default via $PTP1 dev <device #1> src $IP1 proto static 
table <routing table for slow apps>
ip route add default via $PTP2 dev <device #2> src $IP2 proto static 
table <routing table for fast apps>

(Proto static needs kernel patches, but you don't really need this)


-- 
Markus Schulz 
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             reply	other threads:[~2006-08-02 10:08 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-02 10:08 Markus Schulz [this message]
  -- strict thread matches above, loose matches on Subject: below --
2006-07-29 15:33 [LARTC] FWMark routing trouble former03 | Baltasar Cevc

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